Observed Drug Testing Collections

DOT requires an immediate collection under direct observation without any prior notice.

• Delays in notifying drivers may result in legal liability if the driver is in an accident before testing
• Failure to get tested immediately is considered a refusal-to-test

Observed Drug Testing Instructions

Once enrolled, only DOT drug tests ordered through Express Labs are accepted.  If online ordering is unavailable, use the Quest Paper Forms provided by Express Labs.

• Before Testing - Call the collection site to confirm it is open, has a Same-Gender collector and accepting walk-ins.  Most sites will not begin a DOT collection within 3 hours of closing
• Reason for Testing - Return-to-Duty or Follow-Up (Collectors will not observe pre-employment or random)
• Drug Testing – View Instructions

Invalid Result – Abnormal pH

• Urine pH in a DOT drug test should be 4.5–8. Levels outside this range may show tampering, dilution, or substitution and require retesting under direct observation

Invalid Result – Immunoassay Interference

• Interference with creatinine levels from medications, metabolites, or abnormal values may cause false positives or negatives, leading to retesting under direct observation

Invalid Result – Invalid Creatinine

• Creatinine confirms if a urine sample is genuine. Very low or abnormal levels may indicate dilution or substitution, requiring retesting under direct observation

Invalid Result – Bottle A & Bottle B – Different Appearance

• DOT tests split urine into bottle A (primary) and bottle B (split). If the bottles look different, it may signal tampering or contamination and require retesting under direct observation

Invalid Result – Temperature Out-of-Range

• Urine must be 90°F–100°F at collection. Readings outside this range suggest tampering or substitution. Drivers must give a second sample under direct observation or face a refusal-to-test

Invalid Result – Specific Gravity

• Specific gravity checks urine concentration. Out-of-range results may indicate dilution or adulteration and require retesting under direct observation

Express Labs FMCSA Random Drug & Alcohol Consortium
Observed Collections | Updated 2026